Re: Casting the return value of ...

scott@slp53.sl.home (Scott Lurndal) writes:

Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
>

scott@slp53.sl.home (Scott Lurndal) writes:
>

Kaz Kylheku <433-929-6894@kylheku.com> writes:
>

On 2024-03-28, Kenny McCormack <gazelle@shell.xmission.com> wrote:

>
 * Each shared object that simulates a Data Link Processor (DLP),
 * will contain a single namespace-scope function <b>get_dlp</b>
 * which constructs a DLP object of the specified type (for example,
 * a #c_uniline_dlp, #c_card_reader_dlp, et alia).  <b>get_dlp</b>
 * returns the constructed object as a #c_dlp object to the #channel
 * function, which is then used by the I/O subsystem to request
 * services of the DLP at the MLI level.
 */
typedef c_dlp* (*get_dlp_t)(const char *, uint64_t, c_logger *);
...
    get_dlp_t   sym;
...
>
    sym = (get_dlp_t)dlsym(handle, "get_dlp");
    if (sym == NULL) {
        lp->log("Invalid DLP shared object format: %s\n", dlerror());
        unregister_handle(channel);
        dlclose(handle);
        return 1;
    }
>
>

I think there was a time in the development of GCC when there was
a warning even with the cast.  I don't think it's enabled by default
now?

>
We compile with -Wall -Werror and have never seen any warnings related
to casting the result of dlsym(), and we build with GCC[4..13].

>
Do you use -pedantic?  Compiling with -pedantic using gcc 8.4.0
gives a warning diagnostic (and a fatal error if -pedantic-errors
is specified in place of -pedantic).

>
Of course not.  We write production code not standard C (or in this
case, C++) code.    Portability to compilers other than gcc is
not a requirement for the several million line codebase.

It's quite amusing to hear of a team that insists on -Wall but
avoids -pedantic, saving a tiny drizzle of cases (all of which
are easy to remedy) while enduring the ever-changing force 5
blizzard of conditions tested by -Wall.